Glossary of Cardiac Terms
Abdominal aorta - The portion of the aorta in the abdomen.
Ablation - Elimination or removal.
ACE (angiotensin-converting enzyme) Inhibitor - A drug that lowers blood pressure by interfering with the breakdown of a protein-like substance involved in blood pressure regulation.
Acetylcholine - A type of chemical (called a neurotransmitter) that transmits messages among nerve cells and muscle cells.
Alveoli - Air sacs in the lungs where oxygen and carbon dioxide are exchanged.
Ambulatory ECG Monitor - A device worn for an extended period (usually 24 hours) to record heart rhythms for future study. Patients record their daily activity and symptoms while the device records the ECG.
Aneurysm - A balloon-like sac in the wall of an artery, vein, or heart caused by a weakening of the wall by injury, disease, or abnormality present at birth. If left untreated, the bulge may burst or tear causing loss of blood.
Angina or Angina Pectoris - Chest pain that occurs when diseased blood vessels restrict blood flow to the heart. May manifest as pain or discomfort, heaviness, tightness, pressure or burning, numbness aching, tingling in the chest, back, neck, throat, jaw or arms.
Angiography - An x-ray technique that using contrast media or dye injected into the coronary arteries to study blood circulation through the vessels. The test measures the degrees of obstruction to blood flow. Circulation through an artery is not seriously reduced until the inside diameter of the vessel is more than 75% obstructed.
Angiogram - An x-ray of blood vessels or chambers of the heart that shows the course contrast media or dye injected into the bloodstream.
Angioplasty - A non-surgical procedure in which a balloon at the end of a catheter is used to dilate or widen diseased arteries by temporarily inflating the balloon inside the artery. When the obstruction is opened enough to allow sufficient blood to pass through, the catheter is removed.
Annulus - The ring around a heart valve where the valve leaflet merges with the heart muscle.
Antiarrhythmics - Any drug used to control or treat irregular heart beats and slow an overactive heart.
Anticoagulant - Any drug that keeps blood from clotting; a blood thinner.
Antihypertensive - Any drug or other therapy that lowers blood pressure.
Aorta - The largest artery in the body and the initial blood-supply vessel from the heart.
Aortic Valve - The valve that regulates blood flow from the heart into the aorta.
Aphasia - The inability to speak, write or understand spoken or written language because of brain injury or disease.
Arrhythmia (or dysrhythmia) - An abnormal rhythm of the heart.
Arterioles - Small, muscular branches of arteries. When contracted, they increase resistance to blood flow and blood pressure in the arteries.
Artery - A blood vessel conveying oxygenated rich blood in a direction away from the heart.
Arteritis - Inflammation of the arteries.
Arteriosclerosis - A disease process, commonly called hardening of the arteries, which includes a variety of conditions that cause artery walls to thicken and lose elasticity.
Ascending Aorta - The first portion of the aorta, emerging from the heart's left ventricle.
Atherectomy - A non-surgical technique for treating diseased arteries using a catheter and rotating device that cuts or shaves away plaque from artery walls.
Atherosclerosis - A disease process that leads to the accumulation of a waxy substance, called plaque, inside blood vessels. As the interior walls of arteries become lined with plaque, the arteries become narrowed, and the flow of blood through them is reduced.
Atria - The two upper or holding chambers of the heart.
Atrial Flutter - A type of arrhythmia where the upper chambers of the heart (the atria) beat very fast, causing the walls of the lower chambers (the ventricles) to beat inefficiently as well.
Atrial Septum - The wall dividing the right and left atria.
Atrioventricular Block - An interruption or disturbance of the electrical signal between the heart's atria (upper two chambers) and the ventricles (lower two chambers).
Atrioventricular (AV) Node - A group of cells located between the atria (upper two chambers) and the ventricles (lower two chambers) that regulate the electrical current (heart rhythm) that passes through it to the ventricles.
Atrium - Either one of the heart's two upper chambers in which blood collects before being passed to the ventricles.
Autoregulation - When blood flow to an organ remains constant while pressure changes in the artery that delivers blood to that organ may have changed.
Bacterial Endocarditis - A bacterial infection of the heart lining or valves. Individuals with abnormal heart valves or congenital heart defects are at increased risk of developing bacterial endocarditis.
Balloon Catheter - A long tube-like device with a small balloon on the end that can be threaded through an artery.
Balloon Valvuloplasty - A procedure to repair a heart valve using a balloon-tipped catheter threaded through an artery and into the heart. The balloon is inflated to open and separate any narrowed or stiffened flaps (called leaflets) of a valve. The catheter and deflated balloon are removed after the procedure.
Beta Blocker - An antihypertensive drug that limits the activity of epinephrine, a hormone that increases blood pressure.
Biopsy - The process by which a small sample of tissue is taken for examination.
Blood Clot - A mass of blood tissue formed by clotting factors in the blood. Clots stop the flow of blood from an injury, can form inside an artery whose walls are damaged by atherosclerotic build-up, and can cause a heart attack or stroke.
Blood Pressure - The force or pressure exerted by the heart in pumping blood.
Bradycardia - Abnormally slow heartbeat, usually under 50 beats per minute.
Bundle-branch Block - A condition in which portions of the heart's conduction system are defective and unable to conduct the electrical signal normally, causing arrhythmias.
Bypass - Surgery that can improve blood flow to the heart (or other organs and tissues) by providing a new route, or "bypass," around a section of clogged or diseased artery.
Calcium Channel Blocker (or calcium blocker) - A drug that lowers blood pressure by regulating calcium-related electrical activity in the heart.
Capillaries - Microscopically small blood vessels between arteries and veins that distribute oxygenated blood to the body's tissues.
Cardiac Arrest - The stopping of the heartbeat, usually because of interference with the electrical signal (often associated with coronary heart disease).
Cardiac Catheterization - A procedure that involves inserting a fine, hollow tube (catheter) into an artery, usually in the groin area, and passing the tube into the heart. Often used in conjunction with angiography and other procedures, cardiac catheterization has become a common procedure for visualizing the heart and blood vessels and diagnosing and treating heart disease.
Cardiac Enzymes - Complex substances capable of speeding up certain biochemical processes in the cardiac muscle. Abnormal levels of these enzymes signal heart attack.
Cardiac Output - The amount of blood the heart pumps through the circulatory system in one minute.
Cardiopulmonary Bypass - The process by which a machine is used to do the work of the heart and lungs so the heart can be stopped during surgery.
Cardiopulmonary Resuscitation (CPR) - A technique involving a combination of chest compressions and mouth-to-mouth breathing used during cardiac arrest to keep oxygenated blood flowing to the heart muscle and brain until advanced cardiac life support can be initiated or an adequate heartbeat resumes.
Cardioversion - A technique of applying an electrical shock to the chest in order to convert an abnormal heartbeat to a normal rhythm.
Cardiomyopathy - A disease of the heart muscle that leads to generalized deterioration of the muscle and its pumping ability.
Cardiomyoplasty - A procedure that takes muscles from the back or abdomen and wraps them around the heart. The muscle is stimulated by a device similar to a pacemaker and may boost the heart's pumping action.
Carotid Artery - A major artery (right and left) in the neck supplying blood to the brain.
Carotid Duplex Doppler - An ultrasound test done over the neck and the carotid arteries to look for blockages in blood flow to the brain.
Catheter - A thin, flexible tube.
Catheterization - A procedure that involves inserting a fine, hollow tube (catheter) into an artery, usually in the groin area, and passing the tube into the heart. Often used in conjunction with angiography and other procedures, cardiac catheterization has become a prime tool for visualizing the heart and blood vessels and diagnosing and treating heart disease.
Cerebral Embolism - A blood clot formed in one part of the body and then carried by the bloodstream to the brain, where it blocks an artery.
Cerebral Hemorrhage - Bleeding within the brain resulting from a ruptured blood vessel, aneurysm, or a head injury.
Cerebral Thrombosis - Formation of a blood clot in an artery that supplies part of the brain.
Cerebrovascular - Pertaining to the blood vessels of the brain.
Cerebrovascular Accident - Also called cerebral vascular accident, apoplexy or stroke. An impeded blood supply to some part of the brain, resulting in injury to brain tissue.
Cerebrovascular Occlusion - The obstruction or closing of a blood vessel in the brain.
Cholesterol - The most abundant fatty substance in animal tissues. Limited quantities are essential to the normal development of cell membranes. High levels in the diet contribute to the development of atherosclerosis.
Cineangiography - The technique of taking moving pictures to show the passage of an opaque dye through blood vessels, which allows physicians to diagnose diseases of the heart and blood vessels.
Circumflex Artery - The blood vessel that wraps around the left side of the heart.
Claudication - A tiredness or pain in the arms and legs caused by an inadequate supply of oxygen to the muscles, usually due to narrowed arteries.
Collateral Circulation - Blood flow through small, nearby vessels in response to blockage of a main blood vessel.
Commissurotomy - A procedure used to widen the opening of a heart valve that has been narrowed by scar tissue. First developed to correct rheumatic heart disease.
Computed Tomography (CT or CAT scan) - An x-ray technique that uses a computer to create cross-sectional images of the body.
Conduction System - Special muscle fibers that conduct electrical impulses throughout the muscle of the heart.
Congenital - Refers to conditions existing at birth.
Congenital Heart Defects - Malformation of the heart or of its major blood vessels present at birth.
Congestive Heart Failure - The inability of the heart to pump all the blood returning to it, leading to a back up of blood in vessels and accumulation of fluid in body tissues, including the lungs.
Coronary Arteries - Two arteries arising from the aorta that arch down over the top of the heart and divide into branches. They provide blood to the heart muscle.
Coronary Artery Bypass Graft (CABG) - Surgical rerouting of blood around a diseased vessel that supplies the heart by grafting either a piece of vein from the leg or the artery from under the breastbone.
Coronary Artery Disease (CAD) - A narrowing of the inside diameter of arteries that supply the heart with blood. The condition arises from accumulation of plaque and greatly increases a person's risk of having a heart attack.
Coronary Care Unit (CCU) - A specialized facility in a hospital or emergency mobile unit equipped with monitoring devices and staffed with trained personnel design specifically to treat coronary patients.
Coronary Heart Disease - Disease of the heart caused by atherosclerotic narrowing of the coronary arteries likely to produce angina pectoris or heart attack.
Coronary Occlusion - An obstruction of one of the coronary arteries that hinders blood flow to some part of the heart muscle.
Coronary Thrombosis - Formation of a clot in one of the arteries that carry blood to the heart muscle. Also called coronary occlusion.
Cyanosis - Blueness of skin caused by insufficient oxygen in the blood.
Cyanotic Heart Disease - A birth defect of the heart that causes oxygen-depleted (blue) blood to circulate to the body without first passing through the lungs
Deep vein thrombosis - A blood clot in the deep vein in the calf.
Defibrillator - An electronic device that helps reestablish normal contraction rhythms in a malfunctioning heart.
Diabetes (Diabetes Mellitus) - A disease in which the body doesn't produce or properly use insulin. Insulin is needed to convert sugar and starch into the energy needed in daily life.
Diastolic Blood Pressure - The lowest blood pressure measured in the arteries, it occurs when the heart muscle is relaxed between beats.
Digitalis (Digoxin, Digitoxin) - A drug that strengthens the contraction of the heart muscle, slows the rate of contraction of the heart and promotes the elimination of fluid from the body tissues when heart failure is present. In addition, the drug is used in treating certain heart rhythm abnormalities.
Dissecting aneurysm - A condition in which the layers of an artery separate or are torn, causing blood to flow between the layers. Dissecting aneurysms usually happen in the aorta, which is the large vessel that carries blood from the heart to other parts of the body.
Diuretic - A drug that lowers blood pressure by stimulating fluid loss; promotes urine production.
Doppler Ultrasound - A test that uses sound waves to assess blood flow within the heart and blood vessels and to identify leaking valves.
Dysarthria - The imperfect articulation of speech resulting from muscular problems caused by damage to the brain or nervous system.
Dysrhythmia - See Arrhythmia.
Dyspnea - Shortness of breath
Echocardiography - A non-invasive method of studying the heart's structure and function by analyzing sound waves bounced off the heart and recorded by an electronic sensor placed on the chest. A computer processes the information to produce a one-, two- or three-dimensional moving picture that shows how the heart and heart valves are functioning.
Edema - Swelling caused by fluid accumulation in body tissues.
Ejection Fraction - A measurement of blood that is pumped out of a filled ventricle. The normal rate is 50 percent or more.
Electrocardiogram (ECG or EKG) - A test in which several electronic sensors are placed on the body to monitor the electrical conduction system of the heart.
Electroencephalogram (EEG) - A test that can detect and record the brain's electrical activity. The test is done by pasting metal disks, called electrodes, to the scalp.
Electrolytes - Elements or chemicals needed to enable the body and heart to work properly. The most frequently tested by blood test include sodium, potassium and chloride. If the levels are too high or too low in the blood, it cardiac problems may occur.
Electrophysiological Study (EPS) - A test that uses cardiac catheterization to study patients who have arrhythmias. An electrical current stimulates the heart to provoke arrhythmia, which is immediately treated with medication. EPS is used to identify the origin of arrhythmias and test the effectiveness of drugs used to treat abnormal heart rhythms.
Embolus (Embolism) - A blood clot that forms in the blood vessel in one part of the body and travels to another part.
Endarterectomy - Surgical removal of plaque deposits or blood clots in an artery.
Endocardium - The smooth membrane covering the inside of the heart. The innermost lining of the heart.
Endothelium - The smooth inner lining of many body structures, including the heart (endocardium) and blood vessels.
Endocarditis - A bacterial infection of the heart's inner lining (endothelium).
Enlarged Heart - A state in which the heart is larger than normal due to heredity, long-term heavy exercise, or diseases and disorders such as obesity, high blood pressure, and coronary artery disease.
Enzyme - A complex chemical capable of speeding up specific biochemical processes in the body.
Epicardium - The thin membrane covering the outside surface of the heart muscle.
Exercise stress test - A common test used for diagnosing coronary artery disease, especially in symptomatic patients. The test helps assess blood flow through coronary arteries in response to exercise at varied speeds and for various lengths of time on a treadmill. A stress test may include use of electrocardiography, echocardiography, and injected radioactive substances.
Familial Hypercholesterolemia - A genetic predisposition to dangerously high cholesterol levels.
Fatty Acids (Fats) - Substances that occur in several forms in foods; different fatty acids have different effects on lipid profiles.
Fibrillation - Rapid, uncoordinated contractions of individual heart muscle fibers. The heart chamber involved can't contract all at once and pumps blood ineffectively, if at all.
First-degree Heart Block - When an electrical impulse from the heart's upper chambers (the atria) is slowed as it moves through the atria and atrioventricular (AV) node.
Flutter - The rapid, ineffective contractions of any heart chamber. A flutter is considered to be more coordinated than fibrillation.
Fusiform Aneurysm - A tube-shaped aneurysm that causes the artery to bulge outward. Involves the entire circumference (outside wall) of the artery.
Gated Blood Pool Scan - An x-ray analysis of how blood pools in the heart during rest and exercise. The test makes use of a radioactive substance injected into the blood to tag or label red cells. The test provides an estimate of the heart's overall ability to pump and its ability to compensate for one or more blocked arteries. Also called MUGA, for multi-unit gated analysis.
Heart Attack - Medically known as an acute myocardial infarction or MI, refers to the death of, or damage to, part of the heart muscle due to an insufficient blood supply. This occurs when a coronary artery is completely blocked or almost completely blocked and blood and nutrients are not able to reach the part of the heart muscle below the blockage. The severity of the heart attack is a result primarily of the area of the heart that is affected.
Heart Block - General term for conditions in which the electrical impulse that activates the heart muscle cells is delayed or interrupted somewhere along its path.
Heart-lung Machine - An apparatus that oxygenates and pumps blood to the body during open heart surgery.
Heart Valve Prolapse - A condition of the heart valve in which it is partially open when it should be closed.
High Blood Pressure - A chronic increase in blood pressure above its normal range.
High Density Lipoprotein (HDL) - A component of cholesterol, HDL helps protect against heart disease by promoting cholesterol breakdown and removal from the blood; hence, its nickname "good cholesterol."
Holter Monitor - A portable device for recording heartbeats over a period of 24 hours or more.
Hypertension - High blood pressure. A constant measurement in blood pressure above 140/90.
Hypertrophic Obstructive Cardiomyopathy (HOCM) - An overgrown heart muscle that creates a bulge into the ventricle and impedes blood flow.
Hypertrophy - Tissues or organs that have grown in size because of increased workload.
Hyperventilation - Rapid breathing usually caused by anxiety. Persons feel like they can't get enough air, so they breathe heavily and rapidly, which can lead to numb or tingly arms and legs, or fainting.
Hypoglycemia - Low levels of glucose in the blood.
Hypotension - Abnormally low blood pressure
Hypoxia - Less than normal content of oxygen in the organs and tissues of the body.
Implantable Cardioverter/Defibrillator - A device designed to produce an electric shock to control rapid arrhythmias and restore normal heartbeat. It is implanted beneath the skin of the chest and connected to the heart via patches.
Immunosuppressives - Any drug that suppresses the body's immune system. These medications are used to minimize the chances that the body will reject a newly transplanted organ such as a heart.
Impedance Plethysmography - A noninvasive diagnostic test used to evaluate blood flow through the leg.
Incompetent Valve - Also called insufficiency; a valve that is not working properly, causing it to leak blood back in the wrong direction.
Infarct - The area of heart tissue permanently damaged by an inadequate supply of oxygen.
Infective Endocarditis - An infection of the heart valves and the innermost lining of the heart (the endocardium), caused by bacteria in the bloodstream.
Inferior Vena Cava - The large vein returning blood from the legs and abdomen to the heart.
Inotropics - Any drug that increases the strength of the heart's contraction.
Intracoronary Ultrasound - A noninvasive technique that uses sound waves and their echoes to visualize structures and blood flow within the heart.
Intravascular Echocardiography - A marriage of echocardiography and cardiac catheterization. A miniature echo device on the tip of a catheter is used to generate images inside the heart and blood vessels.
Invasive Procedure - Any procedure, test or surgery that involves going through the skin or muscle or into a vein or artery.
Ischemia - Decreased blood flow to an organ, usually due to constriction or obstruction of an artery.
Ischemic Heart Disease - Also called coronary artery disease and coronary heart disease, this term is applied to heart ailments caused by narrowing of the coronary arteries, and therefore characterized by a decreased blood supply to the heart.
Jugular Veins - The veins that carry blood back from the head to the heart.
Left Ventricular Assist Device - A mechanical pumping device that is surgically implanted to help maintain pumping action of the heart. It is often used in patients who are waiting for a heart transplant.
Lesion - An injury or wound. An atherosclerotic lesion is an injury to an artery due to hardening of the arteries.
Lipid - A fatty substance insoluble in blood.
Lipoprotein - A lipid surrounded by a protein; the protein makes the lipid soluble in blood.
Low-density Lipoprotein (LDL) - The body's primary cholesterol-carrying molecule. High blood levels of LDL increase a person's risk of heart disease by promoting cholesterol attachment and accumulation in blood vessels.
Lumen - The hollow area within a tube, such as a blood vessel.
Magnetic Resonance Imaging (MRI) - A technique that produces images of the heart and other body structures by measuring the response of certain elements (such as hydrogen) in the body to a magnetic field. When stimulated by radio waves, the elements emit distinctive signals in a magnetic field. MRI can produce detailed pictures of the heart and its various structures without the need to inject a dye.
Minimally Invasive Heart Surgery - A surgical procedure that is less invasive than conventional coronary artery bypass surgery. A smaller incision allows access to the heart without surgical division of the breastbone and eliminates the need for a heart-lung machine.
Mitral Stenosis - A narrowing of the mitral valve, which controls blood flow from the heart's upper left chamber (the left atrium) to its lower left chamber (the left ventricle). May result from an inherited (congenital) problem or from rheumatic fever.
Mitral valve - The structure that controls blood flow between the heart's left atrium (upper chamber) and left ventricle (lower chamber).
Mitral Valve Prolapse - A condition that occurs when the leaflets of the mitral valve between the left atrium (upper chamber) and left ventricle (lower chamber) bulge into the ventricle and permit backflow of blood into the atrium. The condition is often associated with progressive mitral regurgitation.
Mitral Valve Regurgitation - Failure of the mitral valve to close properly, causing blood to flow back into the heart's upper left chamber (the left atrium) instead of moving forward into the lower left chamber (the left ventricle).
Monounsaturated Fats - A type of fat found in many foods but predominantly in avocados and canola, olive and peanut oil. Monounsaturated fat tends to lower LDL cholesterol levels, and some studies suggest that it may do so without also lowering HDL cholesterol levels.
Mortality - The total number of deaths from a given disease in a population during an interval of time, usually a year.
Mortality Rate (Risk-Adjusted) - A mortality rate that has been standardized for a variety of risk factors so different populations can be compared or the same population can be compared over time.
Murmur - Noises superimposed on normal heart sounds. They are caused by congenital defects or damaged heart valves that do not close properly and allow blood to leak back into the chamber from which it has come.
Myocardial Infarction - The damage or death of an area of the heart muscle (myocardium) resulting from a blocked blood supply to the area. The affected tissue dies, injuring the heart. Symptoms include prolonged, intensive chest pain and a decrease in blood pressure that often causes shock.
Myocardial Ischemia - Deficient blood flow to part of the heart muscle.
Myocardium - The muscular wall of the heart. It contracts to pump blood out of the heart and then relaxes as the heart refills with returning blood.
Myxomatous Degeneration - A connective tissue disorder that causes the heart valve tissue to weaken and lose elasticity.
Nitroglycerin - A drug that helps relax and dilate arteries to enable blood to flow more easily, often used to treat cardiac chest pain (angina). Can be taken by mouth, spray, skin patch, or intravenously.
Necrosis - Referring to the death of tissue within a certain area.
Noninvasive Procedures - Any diagnostic or treatment procedure in which no instrument enters the body.
Nuclear Cardiology - Noninvasive tests to evaluate heart disease using a small amount of radioactive substance injected into a vein. Its presence is detected by a gamma camera. Images reveal areas of the heart that are not getting sufficient blood. Obesity - The condition of being significantly overweight. It is usually applied to a condition of 30 percent or more over ideal body weight.
Obesity - A risk factor in which excessive weight puts a strain on the heart and can increase the chance of developing high blood pressure and diabetes.
Occluded Artery - An artery in which the blood flow has been impaired by a blockage.
Open Heart Surgery - An operation in which the chest and heart are opened surgically while the bloodstream is diverted through a heart-lung (cardiopulmonary perfusion) machine.
Pacemaker - A surgically implanted electronic device that helps regulate the heartbeat.
Palpitation - An uncomfortable sensation within the chest caused by an irregular heartbeat.
Patent Ductus Arteriosus - A congenital defect in which the opening between the aorta and the pulmonary artery does not close after birth.
Percutaneous Transluminal Coronary Angioplasty (PTCA) - See angioplasty.
Pericarditis - Inflammation of the outer membrane surrounding the heart. Rheumatic fever, tuberculosis, and many other agents are its possible causes.
Pericardiocentesis - A diagnostic procedure using a needle to withdraw fluid from the sac or membrane surrounding the heart (pericardium).
Pericardium - The thin, tissue-like sac enclosing the heart and beginning parts of the large blood vessels that leave and enter the heart.
Peripheral Vascular Disease (PVD) - A condition in which blood vessels throughout the body have plaque or disease which reduces blood flow to a particular part of the body such as the legs or kidneys.
Plaque - A deposit of fatty (and other) substances in the inner lining of the artery wall; it is characteristic of atherosclerosis.
Platelets - One of the three types of cells found in blood; they aid in the clotting of the blood.
Polyunsaturated Fat - The major fat constituent in most vegetable oils including corn, safflower, sunflower, and soybean. These oils are liquid at room temperature. Polyunsaturated fat actually tends to lower LDL cholesterol levels but may also reduce HDL cholesterol levels as well.
Positron Emission Tomography (PET) - A test that uses positron emitting substances to assess information about the metabolism of elements that can be used to indicate whether heart muscle is alive and functioning. A ring of radiosensitive detectors positioned around the chest reconstructs a two- or three-dimensional image of the heart.
Premature ventricular contraction (PVC) - An early or extra heartbeat that happens when the heart's lower chambers (the ventricles) contract too soon, out of sequence with the normal heartbeat.
Prevalence - The total number of cases of a given disease that exist in a population at a specific time.
Pulmonary - Referring to the lungs and respiratory system.
Pulmonary Embolism - A condition in which a blood clot that has formed elsewhere in the body travels to the lungs.
Pulmonary Edema - A condition in which there is a fluid accumulation in the lungs caused by an incorrectly functioning heart.
Pulmonary Valve - The heart valve between the right ventricle and the pulmonary artery. It controls blood flow from the heart into the lungs.
Pulmonary Vein - The blood vessel that carries newly oxygenated blood from the lungs back to the left atrium of the heart.
Pulse oximeter - A device that measures the amount of oxygen in the blood.
Radiofrequency ablation (RFA) - A special procedure used to treat heart tissue responsible for causing some fast heart rates.
Radioisotope - A radioactive material injected into the body so that a nuclear scanner can produce images.
Radionuclide imaging - A test in which a harmless radioactive substance is injected into the bloodstream to show information about blood flow through the arteries. Damaged or dead heart muscle can often be identified, as can serious narrowing in an artery.
Radionuclide ventriculography - A diagnostic test used to determine the size and shape of the heart's pumping chambers (the ventricles).
Regurgitation - Backward flow of blood through a defective heart valve.
Renal - Pertaining to the kidneys.
Rheumatic Fever - A disease, usually occurring in childhood, that may follow a streptococcal infection. Symptoms may include fever, sore or swollen joints, skin rash, involuntary muscle twitching, and development of nodules under the skin. If the infection involves the heart, scars may form on heart valves, and the heart's outer lining may be damaged.
Rheumatic Heart Disease - Damage done to the heart, particularly the heart valves, by one or more attacks of Rheumatic Fever.
Risk Factor - An element or condition involving a certain hazard or danger. When referring to heart and blood vessels, a risk factor is associated with an increased chance of developing cardiovascular disease, including stroke.
Nonmodifiable risk factors include family history, age and gender. Modifiable risk factors include smoking, high blood pressure, diet high in fat, sedentary lifestyle, diabetes, stress, type "A" personality, obesity and excessive use of alcohol.
Rotoblade - A high-speed rotating device that connects to the end of a catheter and is used to grind away material that is blocking a coronary artery. Used in an atherectomy, a procedure to open coronary arteries often performed with an angioplasty.
Saccular Aneurysm - A round aneurysm that bulges out from an artery. Involves only part of the circumference (outside wall) of the artery.
Saturated Fat - Type of fat found in foods of animal origin and a few of vegetable origin; they are usually solid at room temperature. Abundant in meat and dairy products, saturated fat tends to increase LDL cholesterol levels, and it may raise the risk of certain types of cancer.
Second-degree Heart Block - Impulses traveling through the heart's upper chambers (the atria) are delayed in the area between the upper and lower chambers (the AV node) and fail to make the ventricles beat at the right moment.
Septal Defect - A hole in the wall of the heart separating the atria or in the wall of the heart separating the ventricles.
Septum - The muscular wall dividing a chamber on the left side of the heart from the chamber on the right.
Shock - A condition in which body function is impaired because the volume of fluid circulating through the body is insufficient to maintain normal metabolism. This may be caused by blood loss or by a disturbance in the function of the circulatory system.
Shunt - A connector that allows blood to flow between two locations. Sick sinus syndrome - The failure of the sinus node to regulate the heart's rhythm.
Silent Ischemia - Episodes of cardiac ischemia that are not accompanied by chest pain.
Sinus (SA) Node - The "natural" pacemaker of the heart. The node is a group of specialized cells in the top of the right atrium which produces the electrical impulses that travel down to eventually reach the ventricular muscle, causing the heart to contract.
Sphygmomanometer - An instrument used to measure blood pressure.
Stent - A device made of expandable, metal mesh that is placed (by using a balloon catheter) at the site of a narrowing artery. The stent is then expanded and left in place to keep the artery open.
Stenosis - The narrowing or constriction of an opening, such as a blood vessel or heart valve.
Stethoscope - An instrument for listening to sounds within the body.
Streptococcal Infection ("strep") - An infection, usually in the throat, resulting from the presence of streptococcus bacteria.
Streptokinase - A clot-dissolving drug used to treat heart attack patients.
Sternum - The breastbone.
Stress - Bodily or mental tension resulting from physical, chemical or emotional factors. Stress can refer to physical exertion as well as mental anxiety.
Stroke (Apoplexy, Cerebrovascular Accident, or Cerebral Vascular Accident) - An onset of symptoms resulting from injury to the brain caused by a blood clot or hemorrhage. This is usually secondary to hypertension, atherosclerosis or both.
Subarachnoid Hemorrhage - Bleeding from a blood vessel on the surface of the brain into the space between the brain and the skull.
Sudden Death - Death that occurs unexpectedly and instantaneously or shortly after the onset of symptoms. The most common underlying reason for patients dying suddenly is cardiovascular disease, in particular coronary heart disease.
Superior Vena Cava - The large vein that returns blood from the head and arms to the heart.
Syncope - A temporary, insufficient blood supply to the brain which causes a loss of consciousness. Usually caused by a serious arrhythmia.
Systolic Blood Pressure - The highest blood pressure measured in the arteries. It occurs when the heart contracts with each heartbeat.
Tachycardia - Accelerated beating of the heart, usually over 110 beats per minute. Paroxysmal tachycardia is a particular form of rapid heart action, occurring in seizures that may last from a few seconds to several days.
Tachypnea - Rapid breathing.
Thallium Stress Test - An x-ray study that follows the path of radioactive potassium carried by the blood into heart muscle. Damaged or dead muscle can be defined, as can the extent of narrowing in an artery.
Third-degree Heart Block (also called Stokes-Adams attack) - Impulses from the heart's upper chambers (the atria) are completely blocked from reaching the heart's lower chambers (the ventricles). To make up for this, the ventricles use their own "backup" pacemaker with its slower rate.
Thrombolysis - The breaking up of a blood clot.
Thrombosis - A blood clot that forms inside the blood vessel or cavity of the heart.
Thrombolytic therapy - Intravenous or intraarterial drugs used to dissolve blood clots in an artery.
Thrombus - A blood clot located in a blood vessel or cavity of the heart.
Tissue Plasminogen Activator (TPA) - A clot-dissolving drug used to treat heart attack patients.
Trans Fat - Created when hydrogen is forced through an ordinary vegetable oil (hydrogenation), converting some polyunsaturates to monounsaturates, and some monounsaturates to saturates. Trans fat, like saturated fat, tends to raise LDL cholesterol levels, and, unlike saturated fat, trans fat also lowers HDL cholesterol levels at the same time.
Transesophageal Echocardiography (TEE) - A diagnostic test that analyzes sound waves bounced off the heart. The sound waves are sent through a tube-like device inserted in the mouth and passed down the esophagus (food pipe), which ends near the heart. This technique is useful in studying patients whose heart and vessels, for various reasons, are difficult to assess with standard echocardiography.
Transient Ischemic Attack (TIA) - A transient (temporary) disruption of blood flow to the brain that may last minutes to hours. Symptoms vary from visual disturbance, speech difficulties, motor weakness, dizziness, numbness or staggering.
Transmyocardial Revacularization (TMR) - A procedure that creates new channels in the heart believed to restore blood flow.
Tricuspid Valve - The structure that controls blood flow from the heart's right atrium (upper chamber) into the right ventricle (lower chamber).
Triglyceride - The most common fatty substance found in the blood; normally stored as an energy source in fat tissue. High triglyceride levels may thicken the blood and make a person more susceptible to clot formation. High triglyceride levels tend to accompany high cholesterol levels and other risk factors for heart disease such as obesity.
Ultrasound - High-frequency sound vibrations, not audible to the human ear, used in medical diagnosis.
Valves - Pieces of tissue in the heart or blood vessels that prevent the backward flow of blood.
Valve Replacement - An operation to replace a heart valve that is either blocking normal blood flow or causing blood to leak backward into the heart (regurgitation).
Valvuloplasty - Reshaping of a heart valve with surgical or catheter techniques.
Varicose Vein - Any vein that is abnormally dilated.
Vascular - Pertaining to the blood vessels.
Vasodilators - Any medication that dilates (widens) the arteries.
Vasopressors - Any medication that elevates blood pressure.
Vein - Any one of a series of blood vessels of the vascular system that carries blood from various parts of the body back to the heart; returns oxygen-depleted blood to the heart.
Ventricle - (Right and Left) One of the two lower chambers of the heart.
Ventricular fibrillation - A condition in which the ventricles contract in a rapid, unsynchronized fashion. When fibrillation occurs, the ventricles cannot pump blood throughout the body.
Ventricular Tachycardia - An arrhythmia (abnormal heartbeat) in the ventricle characterized by a very fast heartbeat.
Vertigo - A feeling of dizziness or spinning.
Wolff-Parkinson-White syndrome - A condition in which an extra electrical pathway connects the atria (two upper chambers) and the ventricles (two lower chambers). It may cause a rapid heartbeat.
X-ray - Form of radiation used to create a picture of internal body structures on film.
Sources: This information provided has been compiled from several online medical resources included those listed on our site.